Guarantor Subsidiaries Financial Information - Condensed Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,111,680	$ 932,253	$ 2,167,857	$ 1,848,287
Cost of sales	(787,713)	(658,290)	(1,533,009)	(1,304,617)
Gross profit	323,967	273,963	634,848	543,670
Total operating expenses	(200,444)	(160,606)	(380,046)	(315,801)
Income from operations	123,523	113,357	254,802	227,869
Interest expense, net	(31,920)	(17,564)	(52,204)	(37,422)
Other income (expense), net	2,171	936	4,757	5,747
Equity earnings (loss)	0	0	0	0
Income from operations before income taxes	93,774	96,729	207,355	196,194
Income tax expense	(10,503)	(24,569)	(36,627)	(52,030)
Net income	83,271	72,160	170,728	144,164
Less: Net loss (gain) attributable to noncontrolling interest	1,145	(135)	2,054	1,750
Net income attributable to Wabtec shareholders	84,416	72,025	172,782	145,914
Comprehensive (loss) income attributable to Wabtec shareholders	(105,801)	219,125	61,573	340,967
Elimination
Condensed Financial Statements, Captions [Line Items]
Net sales	(68,087)	(27,676)	(118,547)	(57,370)
Cost of sales	38,755	20,282	70,834	43,829
Gross profit	(29,332)	(7,394)	(47,713)	(13,541)
Total operating expenses	0	0	0	0
Income from operations	(29,332)	(7,394)	(47,713)	(13,541)
Interest expense, net	0	0	0	0
Other income (expense), net	0	0	0	0
Equity earnings (loss)	(247,515)	(172,678)	(446,319)	(282,475)
Income from operations before income taxes	(276,847)	(180,072)	(494,032)	(296,016)
Income tax expense	0	0	0	0
Net income	(276,847)	(180,072)	(494,032)	(296,016)
Less: Net loss (gain) attributable to noncontrolling interest	0	0	0	0
Net income attributable to Wabtec shareholders	(276,847)	(180,072)	(494,032)	(296,016)
Comprehensive (loss) income attributable to Wabtec shareholders	(276,847)	(180,072)	(494,032)	(296,016)
Parent
Condensed Financial Statements, Captions [Line Items]
Net sales	168,426	137,708	329,727	282,251
Cost of sales	(122,919)	(100,331)	(241,577)	(199,263)
Gross profit	45,507	37,377	88,150	82,988
Total operating expenses	(49,780)	(33,126)	(85,407)	(57,592)
Income from operations	(4,273)	4,251	2,743	25,396
Interest expense, net	(31,734)	(19,805)	(52,128)	(35,488)
Other income (expense), net	483	(8,984)	9,212	5,343
Equity earnings (loss)	128,744	96,963	235,442	165,229
Income from operations before income taxes	93,220	72,425	195,269	160,480
Income tax expense	(7,213)	(401)	(20,895)	(14,567)
Net income	86,007	72,024	174,374	145,913
Less: Net loss (gain) attributable to noncontrolling interest	0	0	0	0
Net income attributable to Wabtec shareholders	86,007	72,024	174,374	145,913
Comprehensive (loss) income attributable to Wabtec shareholders	86,231	72,921	174,881	147,668
Guarantors
Condensed Financial Statements, Captions [Line Items]
Net sales	137,966	93,372	256,083	198,431
Cost of sales	(88,688)	(59,637)	(161,678)	(123,901)
Gross profit	49,278	33,735	94,405	74,530
Total operating expenses	(12,267)	(12,741)	(25,941)	(25,069)
Income from operations	37,011	20,994	68,464	49,461
Interest expense, net	3,137	2,690	6,079	5,230
Other income (expense), net	0	0	(679)	(229)
Equity earnings (loss)	118,771	75,715	210,877	117,246
Income from operations before income taxes	158,919	99,399	284,741	171,708
Income tax expense	0	0	0	0
Net income	158,919	99,399	284,741	171,708
Less: Net loss (gain) attributable to noncontrolling interest	0	0	0	0
Net income attributable to Wabtec shareholders	158,919	99,399	284,741	171,708
Comprehensive (loss) income attributable to Wabtec shareholders	158,919	99,399	284,741	171,708
Non-Guarantors
Condensed Financial Statements, Captions [Line Items]
Net sales	873,375	728,849	1,700,594	1,424,975
Cost of sales	(614,861)	(518,604)	(1,200,588)	(1,025,282)
Gross profit	258,514	210,245	500,006	399,693
Total operating expenses	(138,397)	(114,739)	(268,698)	(233,140)
Income from operations	120,117	95,506	231,308	166,553
Interest expense, net	(3,323)	(449)	(6,155)	(7,164)
Other income (expense), net	1,688	9,920	(3,776)	633
Equity earnings (loss)	0	0	0	0
Income from operations before income taxes	118,482	104,977	221,377	160,022
Income tax expense	(3,290)	(24,168)	(15,732)	(37,463)
Net income	115,192	80,809	205,645	122,559
Less: Net loss (gain) attributable to noncontrolling interest	1,145	(135)	2,054	1,750
Net income attributable to Wabtec shareholders	116,337	80,674	207,699	124,309
Comprehensive (loss) income attributable to Wabtec shareholders	$ (74,104)	$ 226,877	$ 95,983	$ 317,607